From: Elias Fleckenstein <eliasfleckenstein@web.de>
Date: Sun, 13 Feb 2022 16:31:45 +0000 (+0100)
Subject: Implement queue waiting
X-Git-Url: https://git.lizzy.rs/?a=commitdiff_plain;h=04c93844e4e4185d91950f0f5473bc88a84b5461;p=dragonstd.git

Implement queue waiting
---

diff --git a/queue.c b/queue.c
index 04aaccd..37dce73 100644
--- a/queue.c
+++ b/queue.c
@@ -1,16 +1,20 @@
+#include <stdio.h>
 #include <stdlib.h>
 #include "queue.h"
 
 Queue *queue_create()
 {
 	Queue *queue = malloc(sizeof(Queue));
+	queue->cancel = false;
 	queue->list = list_create(NULL);
+	pthread_cond_init(&queue->cv, NULL);
 	pthread_mutex_init(&queue->mtx, NULL);
 	return queue;
 }
 
 void queue_delete(Queue *queue)
 {
+	pthread_cond_destroy(&queue->cv);
 	pthread_mutex_destroy(&queue->mtx);
 	list_clear(&queue->list);
 	free(queue);
@@ -20,6 +24,7 @@ void queue_enqueue(Queue *queue, void *elem)
 {
 	pthread_mutex_lock(&queue->mtx);
 	list_put(&queue->list, elem, NULL);
+	pthread_cond_signal(&queue->cv);
 	pthread_mutex_unlock(&queue->mtx);
 }
 
@@ -30,18 +35,35 @@ void *dequeue(Queue *queue)
 
 void *queue_dequeue_callback(Queue *queue, void (*callback)(void *elem))
 {
-	pthread_mutex_lock(&queue->mtx);
 	void *elem = NULL;
-	ListPair **lptr = &queue->list.first;
-	if (*lptr) {
-		elem = (*lptr)->key;
-		ListPair *next = (*lptr)->next;
-		free(*lptr);
-		*lptr = next;
-
-		if (callback)
-			callback(elem);
+
+	while (! queue->cancel && ! elem) {
+		pthread_mutex_lock(&queue->mtx);
+
+		ListPair **lptr = &queue->list.first;
+		if (*lptr) {
+			elem = (*lptr)->key;
+			ListPair *next = (*lptr)->next;
+			free(*lptr);
+			*lptr = next;
+
+			if (callback)
+				callback(elem);
+		} else {
+			pthread_cond_wait(&queue->cv, &queue->mtx);
+		}
+
+		pthread_mutex_unlock(&queue->mtx);
 	}
-	pthread_mutex_unlock(&queue->mtx);
+
 	return elem;
 }
+
+void queue_cancel(Queue *queue)
+{
+	queue->cancel = true;
+
+	pthread_mutex_lock(&queue->mtx);
+	pthread_cond_broadcast(&queue->cv);
+	pthread_mutex_unlock(&queue->mtx);
+}
diff --git a/queue.h b/queue.h
index 48829cb..80b1e54 100644
--- a/queue.h
+++ b/queue.h
@@ -2,11 +2,15 @@
 #define _DRAGONSTD_QUEUE_H_
 
 #include <pthread.h>
+#include <stdbool.h>
+#include <stdatomic.h>
 #include "list.h"
 
 typedef struct
 {
+	atomic_bool cancel;
 	List list;
+	pthread_cond_t cv;
 	pthread_mutex_t mtx;
 } Queue;
 
@@ -15,5 +19,6 @@ void queue_delete(Queue *queue);
 void queue_enqueue(Queue *queue, void *elem);
 void *queue_dequeue(Queue *queue);
 void *queue_dequeue_callback(Queue *queue, void (*callback)(void *elem));
+void queue_cancel(Queue *queue);
 
 #endif